Electric circuit interrupter



Inventor: Motooki Shinohara, b 1+ fifiwl Attorney Sept 1936- SHINOHARA ELECTRIC CIRCUIT INTERRUPTER Filed July 26, 19:4

Patented Sept. 8, 1936 2,053,973

UNITED STATES PATENT OFFICE 2.053s ELECTRIC CIRCUIT INTERRUPTER Motooki Shinohara, Tokyo, Japan, assignor to General Electric Company, a corporation of New York Application July 26, 1934, Serial No. 737,067 In Japan October 26, 1933 2 Claims. ('01. 200-150) My invention relates to electric circuit interseparation of the contacts, means are provided rupters, more particularly to those of the sofor directly venting the explosion chamber 3 to called explosion chamber type and has for its a region of comparatively low pressure at the principal object the provision of an improved point where separation of contact structures l 5 circuit interrupter of the aforesaid type which and 2 occurs. To this end the contact structure I 5 shall have increased interrupting capacity and is arranged to form a central passage 6 which is be simple and compact in construction and 'efclosed by the rod contact 2 in the closed circuit ficient in operation. position and which serves as a second exhaust My invention will be more fully set forth in the passage for the explosion chamber 3 upon the following description rei erring to the accomseparation of contacts i and 2. 10

panying drawing, and the features of novelty In the specific arrangement shown a stationary which characterize my invention will be pointed adapter 7 of conductingmaterial isprovided with out with particularity in the claims annexed to a plate-like or flange portion 1' which not only and forming apart of this specification. supports the stationary contact structure I but Referring to the drawing, Fig. 1 is an elevaalso the insulating casing or explosion pot 4 as 5 tional view, partly in section, of the contact and indicated at 8 and also forms the upper wall of explosion chamber structure of an electric cirthe explosion chamber. The contact structure cuit interrupter embodying my invention, and I may comprise an annular conducting retainer Fig. 2 is a similar view of another form my inmember 9 suitably secured as by rings I 0 in the g0 vention may assume. wall 1' of the explosion chamber and a plurality In Fig. 1 is shown the contact and explosion of contact segments H which are positioned rachamber structure comprising one pole of an elecdially with respect to the rod contact 2 within tric circuit interrupter of the well-known doublethe retainer 9 and are resiliently biased into conbreak type. A circuit interrupter of this type tact engagement withrod 2 as by garter springs i2.

generally comprises a tank containing a suitable The circuit opening operation is effected by 25 are extinguishing or insulating liquid as oil in lowering of the rod contact 2 into the main oil which both poles of the contact structure are imbody exteriorly of the explosion chamber so that mersed, the movable contact structure comprisboth exhaust passages 5 and 6 of the explosion ing a contact bridging member which is adapted chamber are cleared.

to engage and interconnect the stationary con- Upon initial separation of the contacts within 30 tact structure of both poles and to be lowered the explosion chamber, the arc decomposes the into the arc extinguishing liquid when the ciroil in the explosion chamber at a high rate, gencuit is to be opened. crating gas which creates a high pressure within Referring more particularly to Fig. 1 the stathe chamber. The resulting pressure is effective tionary contact structure I coacts with a movable to direct a blast of oil through the exhaust pas- 35 rod contact 2 within an explosion chamber 3 sage 6 and radially through the are formed beformed by an insulating casing 4 which is comtween the contacts l and 2. Accordingly immeposed of material suitable for withstanding high diately upon separation of the contacts the rebursting pressures. The casing 4 at its lower sulting arc is subjected to an oil blast from the 40 e d s P d d h an e s P sage tthrough explosion chamber. In the event that the are 40 w ich the movable Contact 2 s p d in openis not interrupted when the rod contact 2 clears mg and Closing P circuitthe exhaust passage 5, the pressure within the In the Operatlon of an exphsmn chamber explosion chamber is effective to direct a second cuit interrupter of the conventional type the blast f on thmu h the are at the exhaust pressure generated within the chamber by an are 0 g pa sage 5. The arc is therefore subjected to an oil drawn in the arc extinguishing liquid between the separating contacts is effective to direct a blast b.1853; both i; the gi 3 3 at of said liquid through the explosion chamber exi whenb e p 9 con ac eaves 9 exp haust passage and through the are at said pascham sage when the movable contact has cleared the 2 illustrates another arrangemel, wherein 50 Same Obviously the arc may be drawn through the arc issubjected to a blast of arc extinguishing out the length of the explosion chamber bef re liquid at the time of contact separation and also is ubjected t t are extinguishing blast when the movable rod contact leaves the ex- For the purpose of also subjecting the arc to a plosion chamber. The insulating explosion pot I, 66 blast of the extinguishing liquid shortly after as in the previous instance, is supported by a 55 provided with an insulating plate-like conducting member l5 forming part of the adapter structure I6. The explosion pot 4 is partition ll forming the upper wall of the explosion chamber l8 through the exhaust passage IQ of which the movable rod contact 20 operates. The coacting contact 2! is mounted within the central opening in the partition I! and is resiliently, biased as by a spring 22 to the position limited by the flange 23. The contact 2| is electrically connected as by a flexible lead 24 to the portion l5 of the adapter.

For the purpose of forming a second exhaust passage for venting the explosion chamber i8 directly to a region of comparatively low pressure, the contact 2| is provided with a central passage and communicating ports 25 and 26 respectively opening above the partition H. The

explosion pot is likewise provided with exhaust ports 21 so that in the position of the circuit interrupter illustrated there exist exhaust passages between the explosion chamber l8 and the exterior surrounding oil body.

The movable rod contact 20 is provided with a conical contact portion 20 which engages a corresponding contact surface Zl' at the lower end of the contact 2! so that in the closed circuit position the exhaust passage 25 issubstantially closed. Upon circuit opening movement the contact 2|, by reason of its resilient mounting, re-,-v mains in followingcontact engagement to the position shown and the are initially drawn within the explosion chamber i8 is immediately subjected to a blast of oil from the chamber through the exhaust passage 25. As in the previous case the arc, if not already interrupted, is subjected to a second oil blast in passing through the exhaust passage l9.

It should be understood that my invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:-

1. An electric circuit interrupter comprising an insulating casing forming an explosion chamber having an exhaust passage, said casing being immersed in an arc-extinguishing liquid, a fixed contact mounted in the upper wall of said chamber and forming a second exhaust passage for said chamber terminating beneath the level of said liquid, said second exhaust passage being unobstructed and short as compared with the length of said chamber so that liquid may exhaust freely from said chamber without appreciable back pressure, and a coacting rod contact movable through said first-named exhaust passage for engaging said fixed contact at said second exhaust passage, said rod contact clearing both of said exhaust passages in moving to open circuit position so that are pressure in saidchamber is effective to direct in sequence an arc-extinguishing blast of liquid through each of "said passages.

2. An electric circuit interrupter comprising an insulating casing having a partition forming an explosion chamber and a pressure relief chamber, said casing being immersed in an arc-extinguishing liquid, said explosion chamber having an exhaust passage venting directly exteriorly of said casing and a second exhaust passage in said partition, a relatively fixed contact forming a fiuid passage between said chambers mounted in said second exhaust passage and resiliently biased so as to seat therein, said pressure relief chamber having unobstructed openings directly venting said chamber exteriorly of said casing so that liquid may exhaust freely from said explo-' sion chamber by way of said second exhaust passage without appreciable back pressure, and a coacting rod contact movable through said first exhaust passage for engaging said fixed contact, said rod contact clearing both of said exhaust passages in moving to open circuit position so that are pressure in said chamber is effective to direct in sequence an arc-extinguishing blast through each of said passages.

' MOTOOKI SI-HNOHARA. 

